1. Field
Certain embodiments of the present invention are directed to a prosthetic hip joint, and more particularly to a microprocessor controlled prosthetic hip joint.
2. Description of the Related Art
The occurrence of hip-disarticulation amputations is increasing due to, among other reasons, various armed conflicts. A very limited number of products are available to address this type of amputation by providing some basic function allowing the amputee to stand and walk. Of the products that are currently available, they mainly consist of two types: passive mechanical linkages and hydraulic augmented mechanical linkages.
Passive mechanical linkage hip joints are designed to provide basic support in stance phase, without allowing much swing phase hip motion to occur. However, lack of swing phase motion has been observed to greatly affect the mobility of the user. In most cases, this type of joint allows the user to sit through the use of a spring or elastic member in order for the prosthetic component to clear the socket's distal area that is used while seated.
The hydraulic augmented mechanical linkage type of hip joint provides additional features related to stance and swing motion control. In stance phase, the knee can dampen the motion created by the interaction of the prosthetic foot with the ground (i.e., hip extension) such that gradual rollover is obtained. In turn, during swing phase, the hydraulics can be used in combination with a spring or elastic to control the hip flexion velocity and terminal swing hip flexion angle. However, the stance control employed by hydraulic augmented mechanical hip joints does not allow for stable hip positioning while standing. This results in the user standing in the maximally extended hip position, which has been observed to affect the user's postural stability and cause significant gait deviation when transitioning from static standing to an ambulatory task (e.g., walking). Furthermore, though the combination of the hydraulic damper with the spring or elastic in swing phase allows the user to generate some hip-flexion dynamics, significant effort is required from the user, in the form of pelvic rotation, in order to generate sufficient swing dynamics to place the hip joint in the correct position for the following foot strike.
Accordingly, there is a need for an improved prosthetic hip joint that solves some of the problems noted above and allows for proper stance phase control (in standing and walking) and provides a more natural hip joint movement.